Field Sorting is a way to present information in a specific way without having to configure a Record Type. You can specify the order in which to display fields by the name of the field. For instance, if you always wanted the Last Name just before the First Name then you could put them in that order. If you are using a Record Type this is not used for the data entry screens. Record Types define their own field order. However, this order also affects the search results column order so even though these settings are ignored during the view/edit mode they are still used in the search results screen.